Funny, with systems you usually follow a set of rules, but with your barrier system, i would guess you follow maybe 1-3 particular ones with some other filters, yet Appian Way is from the very outside, while Louie's Backyard is in barrier 1? How can you call it a system if the main criteria can change so much?

Maybe i'm missing something (very likely), or you have a strange set of rules ;-)

chuck